I've been to get my car tested twice and have failed the CO% test both times. Everything else I passed easily. The car is in great shape, everything is in proper tune. The car was running very hot when the tests were done so that won't help. Now the reason I am almost certain it is failing is because I removed the AIR pump from it. There really is no way that I can put it back on (I threw the old pump out) because I have non emissions headers right now (no smog tree). I've heard that disconnecting a vaccuum line can cause the CO to go down. Is this right? Also I've had someone say that putting a small tube with a check valve on it right before the cat will let enough oxygen in to fix it.

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1991 Z28 - 350 TPI, T56, McLeod street clutch, ported plenum & runners, AFPR, Holley Annihilator ignition box and wires, Hooker shorty headers w/o AIR, Flowmaster muffler, homeade ram-air, SSM subframe connectors, Kenny Brown STB, Global West steering box brace, Steve Spohn adjustable torque arm and T56 crossmember

 

The check valve might work, although I don't know anybody that has done this and said it DOES work.

Making a small vac. leak will bring CO down to a point, but HC will go up.

Have you tried adjusting the fuel pressure??

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3

 

hmm, SOunds like you have a helluva predicament. The AIR Pump keeps Co from forming By introducing o2 into the mix.


How Much are you off ?


Try retarding the Timing, and possibly try the Vaccum leak Thing, Alto that May throw your HC out the Roof.

Good Luck, Smog sucks!




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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

 

Yeah I was thinking about dropping the fuel pressure but I'm not sure that would fix it. Idon't have the sheet in front of me but the allowable limit was something around .5 and I was .98 and 1.02 for the two tests. All of the other tests I passed no problem which I can probably attribute to the brand new catalytic convertor. So maybe I have room for some rise in HC levels. Anyone else have some input?

Thanks

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1991 Z28 - 350 TPI, T56, McLeod street clutch, ported plenum & runners, AFPR, Holley Annihilator ignition box and wires, Hooker shorty headers w/o AIR, Flowmaster muffler, homeade ram-air, SSM subframe connectors, Kenny Brown STB, Global West steering box brace, Steve Spohn adjustable torque arm and T56 crossmember

 

Borrow an AIR pump from someone else for a day?

Or..

Befriend someone that does inspections.

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89 iroc-z 305 tbi
k&n filtercharger, open element air filter. nuffin' else

 

My family had an 82 Caddy with the 4.1 tbi. That thing could never pass emission tests. A relative that worked for a caddy dealer suggested thet we pour antifreeze down the throttle body while was running. After it stopped smoking we would take it in to be tested and would pass with flying colors.

Don't remember what test this helped specifically.

YMMV
DB

 

Fill up with '87. If you get a more complete combustion, you should reduce your CO output.

About that anti-freeze thing, well, I won't even justify stupidity.

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'82 Firebird, dead stock, 9 bolt disc rear, over 200,000 miles and still going strong, more to come...
http://www.spinfrenzy.com/stingerssx...easures.html#4

 

Yeah what is that?? I don't think I'll be pouring antifreeze down my intake anytime soon. And stingerssx, doesn't higher octane give more complete combustion? That's what I had always thought at least.

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1991 Z28 - 350 TPI, T56, McLeod street clutch, ported plenum & runners, AFPR, Holley Annihilator ignition box and wires, Hooker shorty headers w/o AIR, Flowmaster muffler, homeade ram-air, SSM subframe connectors, Kenny Brown STB, Global West steering box brace, Steve Spohn adjustable torque arm and T56 crossmember

 

The octane thing is one of the most misunderstood aspects of car life these days.

Ocatne ratings are based on the fuels ability to resist detonation. They have little or nothing to do with actual octane. Originally, the number referred to the ratio of iso-octane to n-heptane. Then when they started adding tetraethyl lead to gasoline, they started using the average of 2 measurement methods, caled "research" octane (the actual chemical composition) and "motor" octane (the detonation resistance thing). The rating on the pump used to even be labelled "M+R/2". With this system, it was possible to get the number to be above 100. They don't use lead now, so the numbers are drastically lower.

If "higher octane" gas actually contained more octane, it might produce more power. However, "premium" pump gas nowadays gets its higher octane from the addition of all sorts of additives that don't actually contribute any energy to the burning process. So regular gas actually has a higher fuel value than "premium", and should be used whenever it doesn't cause a detonation problem. Cars often get as much as 2 mpg better mileage on regular than on premium because of this, especially on the highway. "Premium" contains oxygenates, usually alcohol or MTBE, to lower the comustion rate and therefore the tendency to knock; it also usually will result in lower emissions, since it contains its own built-in oxygen. But you never know: if you're having trouble passing, try them both.

A new catalytic converter would make a world of difference, if you can't get it taken care of any other way. Yours may be so built-up with ash that the catalyst is no longer exposed to the exhaust gas, which severely limits its usefulness.

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"So many Mustangs, so little time..."
ICON Motorsports

 

Just a note, introducing a vacuum leak will just increase your idle speed. Thats it, plain and simple.
Why, cuz you have speed density. Speed density doesn't care where air enters, it only knows the pressure and temperature in the manifold. Introducing a vaccum leak lowers the MAP, which increase your fuel. More air, more fuel = more rpms.
Of course if the vacuum leak is small enough the IAC will compensate and lower your idle back down.
Don't believe me, while your car is running disconnect the big power brake booster line. Magic.
...ed

 

Well I wasn't planning on diconnecting a vacuum line as big as the power brake booster line. But when I disconnect the fuel pressure regulator vacuum line the rpms will increase slightly but then come back down, I guess because of the IAC.

And RB83L69, the catalytic convertor is brand new. That's why all of my other readings were so low.

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1991 Z28 - 350 TPI, T56, McLeod street clutch, ported plenum & runners, AFPR, Holley Annihilator ignition box and wires, Hooker shorty headers w/o AIR, Flowmaster muffler, homeade ram-air, SSM subframe connectors, Kenny Brown STB, Global West steering box brace, Steve Spohn adjustable torque arm and T56 crossmember

 

This guy with a mustang passed with no cats by pouring a gallon of denatured alchohal to a 1/4 tank of gas. Higher octain ratings mean less emmisions. If you use 87 it will make dirtier emissions than 93.

 

I got my car to pass it ATL running on amoco ultimate. Don't know if that had anything to do with it or not. But like you, I have non emissions headers (and a non computer controlled carb). I did have to adjust the timing and mixture a little though. Now that I get to thinking about it, the guys at the shop did the adjustments to make it pass and then set it back how it was for me. That was the BP on Hwy. 138 in Conyers just off I-20 if you care.

 

High CO? How's your air filter? Throw a new $6 K-mart special in there... your motor's might just not be getting enough air.

(Of course usually high HC goes with high CO to show a rich mixture, but $6 can't hurt.)


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

High HC is usaully typical of incomplete combustion, not necessarily a rich mixture (although an overly rich mixture will nail this too).
High CO readings are typical of a rich mixture and overly rich will nail both. CO occurs when there is not enough oxygen to support complete combustion.
Here are examples; High HC due to dead cylinder. High CO due to using plugs that are too cold for your application.
A cheesy way to pass is to bump up your idle a tad, add some gas-line anti-freeze, and lower your fuel pressure. Some octane booster may also help, as well as some emissions specific gas additives.

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"Question with boldness even the existence of a God; because, if there be one, he must more approve of the homage of reason, than that of blind-folded fear."

-Thomas Jefferson

 

If you were close, I would say try some fuel injector cleaner. It worked for my friend. Oh well, just my .02

 

Steve,

You might be in the market for an A.I.R. pump soon. If you don't have the visual inspection (only the exhaust gas analysis) and don't need to have a stock A.I.R. pump in place, you can install a used-but-nice electric pump from a later LT1 and route a hose directly to the cat. During normal operation the air is delivered to the cat anyway, and none is delivered to the exhaust manifolds/headers. You don't have to drill holes and weld fittings in the headers, just run an aspirator tube and check valve to the converter. Wire the A.I.R. pump to a hidden dash switch and let it run during the test. Then turn it off until next year. You can locate the pump in any remote area, like an inner fender opposite the battery, or in front of the radiator support. Hose is pretty cheap.

If you do this, you might want to run the pump once in a while just to keep it moving. I've had two fail on LT1s probably because of moisture collected while sitting in storage.

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Later,
Vader
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"I'm gonna talk about some freaky sheet now..."
Adobe Acrobat Reader 4.0
KaleCo Auto Parts

 

Anyone else have some ideas? I need to get this thing passed by Sunday. Thanks

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1991 Z28 - 350 TPI, T56, McLeod street clutch, ported plenum & runners, AFPR, Holley Annihilator ignition box and wires, Hooker shorty headers w/o AIR, Flowmaster muffler, homeade ram-air, SSM subframe connectors, Kenny Brown STB, Global West steering box brace, Steve Spohn adjustable torque arm and T56 crossmember